/Engine/Source/Runtime/Engine/Classes/Components/PrimitiveComponent.h
Walks up the attachment tree until a primitive component with LightAttachmentsAsGroup enabled is found. This component will effectively act as the root of the attachment group. Return nullptr if none is found.
const [UPrimitiveComponent](API\Runtime\Engine\Components\UPrimitiveComponent) * GetLightingAttachmentRoot() const